WO2019151092A1

WO2019151092A1 - Scanning device and distance measuring device

Info

Publication number: WO2019151092A1
Application number: PCT/JP2019/002155
Authority: WO
Inventors: 加園　修; 佐藤　充; 柳澤　琢麿
Original assignee: パイオニア株式会社
Priority date: 2018-01-30
Filing date: 2019-01-24
Publication date: 2019-08-08

Abstract

Provided is a scanning device which can measure distance within a distance-measurement region by means of a scanning mode having a desirable density distribution locus. This scanning device has: an emission unit that emits light; an optical scanning unit that transmits the light towards a first region and a second region, which are adjacent to each other, by cyclically changing the transmission direction of the light; and an optical path control unit that guides a first scanning light to a first scanning region, said first scanning light having been transmitted from the optical scanning part towards the first region, and that guides a second scanning light to a second scanning region, said second scanning light having been transmitted towards the second region. The optical path control unit is configured so as to be able to change the positional relationship of the first scanning region and the second scanning region by changing the optical path of the first scanning light and the second scanning light.

Description

Scanning device and distance measuring device

The present invention relates to a scanning device and a distance measuring device that perform optical distance measuring.

A distance measuring device that scans light within a target area and measures the distance to an object is known. Such a distance measuring device has, for example, a light source that emits a laser pulse, a scanning mechanism that reflects and scans the laser pulse, and a light receiving unit that receives the laser pulse reflected by an object. . The distance measuring device measures the distance to the object based on the emission time of the laser pulse emitted by the light source and the light reception time of the laser pulse received by the light receiving unit.

For example, in Patent Document 1, an optical scanning unit that has a light reflecting surface and can perform Lissajous scanning of light incident on the light reflecting surface within a target region, and pulsed light emitted from the light source unit is reflected by an object. A light receiving section that receives the reflected light, and a distance measuring section that measures the distance of the object based on the emission timing of the pulsed light from the light source section and the reception timing of the reflected light from the light receiving section. A distance device is disclosed.

JP 2011-53137 A

In the distance measuring apparatus as described above, distance measurement is performed by so-called Lissajous scanning in which pulsed light is irradiated along a Lissajous locus. The Lissajous locus has a low scanning locus density in the central region of the scanning region and a high scanning locus density in the edge region.

For example, in a distance measuring device, it is often necessary to perform detailed distance measurement in the central region of the scanning region. In such a case, it is difficult to measure a desired quality in an area having a high scanning density, such as a Lissajous trajectory. .

The present invention has been made in view of the above points, and one object of the present invention is to provide a distance measuring device capable of distance measurement by a scanning mode having a locus of a desired density distribution within an area for distance measurement. It is said.

According to the first aspect of the present invention, the light is emitted toward the first region and the second region adjacent to each other by periodically changing the light emitting direction and the irradiation direction of the light. An optical scanning unit to be irradiated, and a second scanning that is directed toward the first scanning region from the optical scanning unit to the first scanning region and is irradiated toward the second region An optical path control unit that guides light to a second scanning region, and the optical path control unit changes the optical path of the first scanning light and the second scanning light to change the first scanning region and The scanning device is configured to be able to change the positional relationship of the second scanning region.

According to the seventh aspect of the present invention, the light is emitted toward the first region and the second region adjacent to each other by periodically changing the light emitting direction and the irradiation direction of the light. An optical scanning unit to be irradiated, and a second scanning that is directed toward the first scanning region from the optical scanning unit to the first scanning region and is irradiated toward the second region An optical path controller that guides light to the second scanning region, and reflected light reflected by the first scanning light or the second scanning light reflected by an object existing in the first scanning region or the second scanning region And a distance measuring unit that measures the distance to the object based on the reflected light received by the light receiving unit, and the optical path control unit includes the first scanning light and the second scanning light. By changing the optical path of the scanning light, the positional relationship between the first scanning region and the second scanning region is changed. It is distance measuring apparatus according to claim are configured to allow Rukoto.

FIG. 1 is a block diagram illustrating the configuration of the distance measuring apparatus according to the embodiment. FIG. 2A is a top view of the scanning unit according to the embodiment. FIG. 2B is a cross-sectional view of the scanning unit according to the embodiment. FIG. 3 is an explanatory diagram illustrating a scanning mode of the scanning unit of the distance measuring apparatus according to the embodiment. FIG. 4 is an explanatory diagram illustrating an example of a waveform of a drive signal applied to the scanning unit according to the embodiment and a scanning trajectory of pulsed light by the scanning unit. FIG. 5 is an explanatory diagram showing an aspect in which the scanning light is reflected by the reflecting mirror section. FIG. 6 is an explanatory diagram showing an aspect of emitted light reflected by the reflecting mirror section. FIG. 7 is a diagram showing the locus of the emitted light irradiated on the scanning plane in FIG. FIG. 8 is a view showing a region of the locus of the emitted light irradiated on the scanning plane of FIG. FIG. 9 is a diagram showing a locus region of the emitted light irradiated on the scanning surface in FIG. FIG. 10 is an explanatory diagram illustrating an aspect in which the scanning light is reflected by the reflecting mirror portion of the scanning device according to the second embodiment. FIG. 11 is an explanatory diagram illustrating an aspect of emitted light reflected by the reflecting mirror portion of the scanning device according to the second embodiment. FIG. 12 is a diagram showing the locus of the emitted light irradiated on the scanning surface in FIG. FIG. 13 is a perspective view illustrating a configuration example of the reflecting mirror portion of the scanning device according to the third embodiment.

The configuration of the distance measuring apparatus 10 according to the embodiment will be described with reference to FIG. The distance measuring device 10 is a distance measuring device that optically measures the distance to the object OB. Specifically, the distance measuring device 10 irradiates light toward a predetermined spatial region, that is, the scanning target region R. In addition, the distance measuring device 10 receives the light reflected by the object OB, and measures the distance from the object OB, that is, measures the distance.

The light source 20 is a light emitting element such as a laser diode capable of emitting the pulsed light L1, and functions as an emitting unit.

The optical system OS is provided on the optical path of the pulsed light L1. The optical system OS includes an optical member such as a collimator lens, and converts the pulsed light L1 emitted from the light source 20 into parallel light.

A beam splitter BS is provided on the optical path of the pulsed light L1. Specifically, the pulsed light L1 emitted from the light source 20 is converted into parallel light by the optical system OS and passes through the beam splitter BS. The beam splitter BS is arranged to transmit or reflect incident light incident on the beam splitter BS in a predetermined direction. In this embodiment, the beam splitter BS transmits the pulsed light L1 emitted from the light source 20.

The MEMS (Micro Electro Mechanical Systems) mirror device 30 is provided on the optical path of the pulsed light L1. Specifically, the pulsed light L1 is applied to the MEMS mirror device 30 after passing through the optical system OS and the beam splitter BS. The MEMS mirror device 30 has a reflective surface 30S that reflects the pulsed light L1. The reflective surface 30S is made of, for example, a light reflecting film that reflects the pulsed light L1.

The MEMS mirror device 30 generates the scanning light L2 by reflecting the pulsed light L1 with a reflecting member. In addition, the MEMS mirror device 30 continuously changes the emission direction of the scanning light L2 by swinging the reflecting member.

The light source control unit 13 is a drive circuit that drives the light source 20. The light source controller 13 has a timing table (not shown) for emitting the pulsed light L1 from the light source 20. The light source control unit 13 provides a drive signal to the light source 20 with reference to the timing table.

The scanning control unit 14 generates a drive signal for swinging the reflecting member of the MEMS mirror device 30 and supplies the generated drive signal to the MEMS mirror device 30.

In the MEMS mirror device 30, the reflecting member swings based on the drive signal generated by the scanning control unit 14. Therefore, the direction in which the pulsed light L1 is reflected by the MEMS mirror device 30, that is, the irradiation direction, changes sequentially. As described above, the MEMS mirror device 30 reflects the pulsed light L1 to generate the scanning light L2. Specifically, the MEMS mirror device 30 generates, as first scanning light, scanning light L2 that is emitted toward a first region in a virtual surface SS1 described later. Further, the MEMS mirror device 30 generates, as the second scanning light, the scanning light L2 that is emitted toward the second region of the virtual surface SS1 described later. That is, the light source 20 and the MEMS mirror device 30 function as an optical scanning unit that scans the scanning light L2 in a predetermined irradiation direction.

The reflecting mirror unit 40 is a mirror member disposed in the irradiation range of the scanning light L2 generated by the MEMS mirror device 30. The reflecting mirror unit 40 has a reflecting surface 41 on the surface facing the MEMS mirror device 30. The scanning light L 2 is reflected by the reflecting surface 41 of the reflecting mirror unit 40 and is emitted toward the scanning target region R. Accordingly, the reflecting mirror unit 40 functions as an optical path control unit (reflecting unit) that controls the optical path of the scanning light L2.

In the present embodiment, the scanning light L2 emitted from the MEMS mirror device 30 is directly applied to the reflecting mirror unit 40. However, the scanning light L2 emitted from the MEMS mirror device 30 may be indirectly irradiated onto the reflecting mirror unit 40. For example, the scanning light L2 emitted from the MEMS mirror device 30 may be applied to the reflecting mirror unit 40 via an optical member such as a mirror. That is, when the scanning light L 2 is indirectly applied to the reflecting mirror unit 40, the reflecting mirror unit 40 may not have the reflecting surface 41 on the surface facing the MEMS mirror device 30.

Here, in FIG. 1, a virtual surface that is separated from the MEMS mirror device 30 in the scanning target region R by a predetermined distance is shown as a scanning target surface S1. Note that the scan target surface S1 does not actually exist, but is illustrated for the purpose of explaining the present embodiment.

The emission direction of the scanning light L2 emitted from the MEMS mirror device 30 continuously changes over time due to the oscillation of the reflective surface 30S of the MEMS mirror device 30. Accordingly, the locus of the emitted light L3 is drawn on the scanning target surface S. In addition, the irradiation range with respect to the reflective mirror part 40 of the scanning light L2 is determined according to the angular range in which the reflective member of the MEMS mirror apparatus 30 can swing.

When there is an object OB (an object having a property of reflecting the emitted light L3) on the optical path of the emitted light L3 in the scanning target region R, the emitted light L3 is reflected by the object OB.

The reflected light L4 obtained by reflecting the emitted light L3 by the object OB is reflected again by the reflecting surface 41 of the reflecting mirror section 40 and enters the MEMS mirror device 30. The reflected light L4 reflected by the reflective surface 30S of the MEMS mirror device 30 is reflected again by the beam splitter BS and enters the light receiving unit 50.

The light receiving unit 50 is disposed on the optical path of the reflected light L4 reflected by the beam splitter BS. The light receiving unit 50 is a photodetector that generates a light reception signal based on the intensity of light incident on the light receiving unit 50. As such a photodetector, a light receiving element such as an avalanche photodiode can be used.

The reflected light L4 reflected by the beam splitter BS is converted into a received light signal by the light receiving unit 50. The changed received light signal is supplied to the distance measuring unit 60.

The distance measuring unit 60 measures the distance between the light receiving unit 50 and the object OB based on the pulsed light L1 emitted from the light source 20 and the reflected light L4 received by the light receiving unit 50. For example, the distance measuring unit 60 includes a signal processing circuit, and calculates distance data of the object OB by calculation. As an example of calculating the distance data, a time-of-flight method can be used.

Specifically, the light source control unit 13 supplies an emission signal including the time (timing) when the light source 20 emits the pulsed light L1 to the distance measuring unit 60. The light reception signal generated by the light receiving unit 50 includes the timing at which the reflected light L4 is received. The distance measuring unit 60 measures the distance from the distance measuring device 10 to the object OB based on the difference between the timing at which the light source 20 emits the pulsed light L1 and the timing at which the light receiving unit 50 receives the reflected light L4. To do.

A configuration example of the MEMS mirror device 30 will be described with reference to FIGS. 2A and 2B. FIG. 2A is a schematic top view of the MEMS mirror device 30. 2B is a cross-sectional view taken along line VV in FIG. 2A.

As shown in FIGS. 2A and 2B, the fixing portion 31 includes a fixed substrate B1 and a fixed frame B2 that is an annular frame formed on the fixed substrate B1. As shown in FIG. 2B, the fixed substrate B1 has a protrusion B1P having a frame-like planar shape on the upper surface B1S of the fixed substrate B1 in a region facing the fixed frame B2, and is fixed on the protrusion B1P. The frame B2 is placed.

The movable portion 32 is disposed inside the fixed frame B2, and includes a swing plate SY and a swing frame SX surrounding the swing plate SY. A circular light reflecting film 33 is provided on the rocking plate SY as the reflecting member. Hereinafter, the upper surface of the light reflecting film 33, that is, the center of the reflecting surface 30S is described as AC.

The swing frame SX is connected to the fixed frame B2 by the first torsion bar TX. The first torsion bar TX is a pair of long plate-like structural portions that extend along a first swing axis AX that passes through the center AC of the reflective surface 30S and extends in the in-plane direction of the reflective surface 30S. When a force around the swing axis AX is applied to the swing frame SX, the first torsion bar TX is twisted, and the swing frame SX is centered on the first swing axis AX, that is, the first swing axis AX is moved. It swings as the swing center axis. The swing frame SX has a line-symmetric shape about the first swing axis AX.

The swing plate SY is connected to the swing frame SX by the second torsion bar TY. The second torsion bar TY passes through the center AC of the light reflecting film, extends in the in-plane direction of the reflecting surface 30S, and extends along the second swing axis AY that is orthogonal to the first swing axis AX. It is a pair of elongated plate-like structural parts. When a force around the swing axis AY is applied to the swing plate SY, the second torsion bar TY is twisted, and the swing plate SY is centered on the second swing axis AY, that is, the second swing shaft AY is moved. It swings as the swing center axis. The swing plate SY has a line-symmetric shape about the swing axis AY.

Therefore, the swing plate SY swings about swing axes AX and AY orthogonal to each other. The direction in which the reflecting surface 30S faces is changed by the swing of the swing plate SY.

As described above, the movable portion 32 is connected to the fixed frame B2, and the fixed portion B2 is placed on the protruding portion B1P of the fixed substrate B1. Therefore, the movable part 32 is separated from the upper surface B1S of the fixed substrate B1. When the swing frame SX swings about the swing axis AX and the swing plate SY swings about the swing axis AY, the movable portion 32 swings so as to tilt with respect to the fixed frame B2. The protruding portion B1P is formed with a sufficient height such that the movable portion 32 does not contact the upper surface B1S due to the swinging. Note that, for example, the fixed frame B2 and the movable portion 32 may have an integrated structure formed by processing from one semiconductor substrate.

The driving force generator 34 includes a permanent magnet MG1 and a permanent magnet MG2 disposed outside the protrusion B1P on the fixed substrate B1, and a metal drawn around the outer periphery of the swing frame SX on the swing frame SX. A wiring (first coil) CX and a metal wiring (second coil) CY routed along the outer periphery of the swing plate SY on the swing plate SY are included.

Permanent magnet MG1 is a pair of magnet pieces arranged on swinging axis AX and provided to face each other with movable part 32 interposed therebetween. The permanent magnet MG2 is a pair of magnet pieces that are arranged on the swing axis AY and are opposed to each other with the movable portion 32 interposed therebetween. Therefore, in this embodiment, four magnet pieces are arranged so as to surround the movable portion 32.

Further, the two magnet pieces constituting the permanent magnet MG1 are arranged so that the portions having opposite polarities are opposed to each other. Similarly, the two magnet pieces constituting the permanent magnet M2 are arranged such that portions having opposite polarities are opposed to each other.

The scanning control unit 14 is connected to the metal wirings CX and CY. The scanning control unit 14 supplies current (drive signal) to the metal wirings CX and CY. The driving force generator 34 generates an electromagnetic force that swings the swing frame SX and the swing plate SY of the movable unit 32 by applying the drive signal.

Specifically, when a current flows through the metal wiring CX, the current and the magnetic field generated by the two magnet pieces of the permanent magnet MG1 arranged in the direction along the swing axis AY are swung. A force around the swing axis AX is applied to the frame SX. Accordingly, the first torsion bar TX is twisted around the swing axis AX, and the swing frame SX swings around the swing axis AX.

Further, when a current flows through the metal wiring CY, the current swings on the swing plate SY due to the interaction between the current and the magnetic field generated by the two magnet pieces of the permanent magnet MG2 disposed in the direction along the swing axis AX. A force around the axis AY is applied. As a result, the second torsion bar TY is twisted around the swing axis AY, and the swing plate SY swings about the swing axis AY.

FIG. 3 shows a mode in which the scanning light L2 is emitted from the MEMS mirror device 30. In FIG. 3, when the pulsed light L1 is incident on the MEMS mirror device 30, it is reflected by the reflective surface 30S to generate the scanning light L2.

The reflecting mirror unit 40 is arranged in a spatial region in the irradiation direction as viewed from the MEMS mirror device 30. Here, the position of the swing plate SY when no voltage is applied to the MEMS mirror device 30 is defined as a reference position. The optical axis AZ is the axis of the scanning light L2 at which the pulsed light L1 is reflected by the reflecting surface 30S at the reference position of the swing plate SY.

In FIG. 3, it is assumed that the scanning light L 2 is transmitted through the reflecting mirror portion 40 in the emission direction of the scanning light L 2 emitted from the MEMS mirror device 30 and behind the reflecting surface 41 of the reflecting mirror portion 41. A virtual plane SS1 which is a scanning plane in this case is shown. Between the virtual surface SS1 and the reflecting mirror section 40, transmitted light L2 'that is the scanning light L2 when the scanning light L2 is assumed to pass through the reflecting mirror section 40 is depicted. Note that the virtual surface SS1 and the transmitted light L2 'do not actually exist, but are illustrated for explanation of the present embodiment.

The virtual surface SS1 has a first region and a second region that are adjacent to each other. In the present embodiment, the first region is a region to which transmitted light L2 'transmitted through a first reflecting surface 41L described later is irradiated. In the present embodiment, the second region is a region irradiated with transmitted light L2 'that has passed through a second reflecting surface 41R described later.

FIG. 4 shows the relationship between the drive signals DX and DY generated by the scanning control unit 14 when the MEMS mirror device 30 performs the Lissajous scanning, and the scanning locus of the scanning light L2 scanned by the MEMS mirror device 30 based on this. Is schematically shown.

In the following description, the drive signal DX will be described as a drive signal generated by the scanning control unit 14 and supplied to the metal wiring CX. As a result, the swing frame SX swings around the swing axis AX. The drive signal DY will be described as a drive signal generated by the scanning control unit 14 and supplied to the metal wiring CY. As a result, the swing plate SY swings around the swing axis AY.

In the following description, the amplitudes of the drive signal DX and the drive signal DY are all equivalent (AMP = 1 in the figure).

4A shows a scanning locus TR of the transmitted light L2 'drawn on the virtual surface SS1 shown in FIG. AX1 and AY1 in the figure correspond to the swing axis AX and the swing axis AY of the MEMS mirror device 30, respectively. That is, the swing of the MEMS mirror device 30 about the swing axis AX corresponds to the change in the scanning position in the direction along AY1 in the virtual plane SS1. Further, the swing of the MEMS mirror device 30 about the swing axis AY corresponds to a change in the scanning position in the AX1 direction on the virtual surface SS1.

FIG. 4B schematically shows the waveform of the drive signal DX at the time of the Lissajous scanning shown in FIG. The drive signal DX in FIG. 4B is a sine wave represented by the formula DX (θ ₁ ) = A ₁ sin (θ ₁ + B ₁ ), where A ₁ and B ₁ are constants and θ ₁ is a variable. Signal. The variable θ ₁ corresponds to the drive signal DX corresponding to the natural frequency of the swing frame SX and the swing plate SY supported by the fixed frame B 2 by the first torsion bar TX of the MEMS mirror device 30. It is set to be a sine wave of the frequency to be used.

FIG. 4C schematically shows the waveform of the drive signal DY during the Lissajous scanning shown in FIG. The drive signal DY is a sine wave signal represented by an equation DY (θ ₂ ) = A ₂ sin (θ ₂ + B ₂ ), where A ₂ and B ₂ are constants and θ ₂ is a variable. Variable theta _2, the drive signal DY is, corresponds to the natural frequency of the oscillating plate SY of the MEMS mirror device 30, it is set this to a sine wave of a frequency to resonate.

Therefore, the swing frame SX and the swing plate SY are swung while resonating around the swing axis AX by the drive signal DX. That is, it is driven in the resonance mode operation mode around the swing axis AX. Further, the swing plate SY is swung while resonating around the swing axis AY by the drive signal DY. Therefore, the swing plate SY swings about the swing axis AX and swings about the swing axis AY. The direction in which the light reflecting film 33 faces changes according to the swing of the swing plate SY. Accordingly, the pulsed light L1 emitted from the light source 20 is reflected by the light reflecting film 33, and is emitted toward the reflecting mirror unit 40 as the scanning light L2 while changing the emission direction according to the oscillation of the oscillation plate SY. .

As shown in FIG. 4A, as described above, the swing plate SY swings while resonating around the swing axis AX and the swing axis AY. Accordingly, the trajectory TR of the irradiation point (spot position) of the transmitted light L2 'on the virtual surface SS1 is drawn along the Lissajous curve.

In the end region in the direction along the axis AX1 of the virtual surface SS1, a dense region having a high locus density is formed. A sparse region having a low trajectory density is formed in the central region arranged near the center in the direction along the axis AX1 of the virtual surface SS1. That is, as the distance from the end region approaches the central region, the distance between the tracks becomes wider than that of the end region. Further, when the pulsed light L1 is emitted at equal intervals, the scanning speed is slower in the end region than in the central region, so that the spatial spacing of the pulsed light is high in the end region, and the density in the central region. Lower.

Referring back to FIG. 3, the reflecting mirror section 40 has a first member 40a formed in a rectangular plate shape and a second member 40b formed in a rectangular plate shape. The first member 40a and the second member 40b are connected to each other via a hinge H.

The reflective surface 41 is provided on the surface of the first member 40a and the second member 40b facing the MEMS mirror device 30. The reflecting surface 41 is made of a light reflecting film. The reflection surface 41 is disposed so as to face the reflection surface 30 S of the MEMS mirror device 30.

The reflecting surface 41 of the reflecting mirror section 40 has a first reflecting surface 41L and a second reflecting surface 41R. The first reflecting surface 41L is provided on the surface of the first member 40a facing the MEMS mirror device 30. The second reflecting surface 41R is provided on the surface of the second member 40b facing the MEMS mirror device 30. In other words, the second reflecting surface 41R is configured by the first member 40a. The first reflecting surface 41L is configured by the second member 40b.

The hinge H includes a shaft SH formed along the axial direction of the rotation axis AR1, a first connecting portion (not shown) that is rotatable around the axis of the shaft SH, and an axis around the shaft SH. A second connection portion (not shown) that is rotatable and provided at a predetermined angle with the first connection portion. The 1st member 40a of the reflective mirror part 40 is connected to the 1st connection part, and the 2nd member 40b of the reflective mirror part 40 is connected to the 2nd connection part. That is, the second reflecting surface 41R and the first reflecting surface 41L are connected so as to be rotatable with respect to each other. The first connecting portion and the second connecting portion include a stopper (not shown) that can be fixed at a desired angular position formed by the first member 40a and the second member 40b.

Thus, the first member 40a and the second member 40b are connected to each other via the hinge H. Accordingly, the second reflecting surface 41R and the first reflecting surface 41L are variable in angle with respect to each other, and the second reflecting surface 41R and the first reflecting surface are controlled by an actuator (not shown) controlled by the reflecting mirror control unit 15. The angle with the surface 41L can be controlled.

FIG. 5 shows an aspect of the scanning light L2 reflected by the reflecting mirror unit 40 as viewed from the direction along the axis AR1 of the reflecting mirror unit 40. The thickness of the arrow in the figure depends on the density of the trajectory. That is, a thick arrow indicates that the locus density is high, and a thin arrow indicates that the locus density is low. Further, the scanning light L2 traveling toward the first reflecting surface 41L is referred to as first scanning light L2F, and the scanning light L2 traveling toward the second reflecting surface 41R is referred to as second scanning light L2S.

In FIG. 5, of the two scanning lights L2 emitted at the maximum oscillation angle of the oscillation plate SY around the oscillation axis AY of the MEMS mirror device 30, the scanning light L2S emitted at one maximum oscillation angle. The ray is L2R, and the ray of the scanning light L2F emitted at the other maximum swing angle is L2L.

The angle formed by the two rays L2R and L2L, that is, the irradiation angle that is the irradiation range of the scanning light L2 around the oscillation axis AY is defined as an angle θ. Of the angles formed by the first reflecting surface 41L and the second reflecting surface 41R, the angle facing the emitting direction of the emitted light L3 is defined as an angle D1.

In other words, the angle D1 is an angle formed by the first reflecting surface 41L and the second reflecting surface 41R with respect to the incident direction of the first scanning light L2F or the second scanning light L2S to the reflecting mirror section 40. is there. An angle obtained by subtracting the angle D1 from 180 degrees is defined as an angle Y.

In the present embodiment, the two first reflecting surfaces 41L and the second reflecting surface 41R are arranged so as to be line symmetric with respect to the optical axis AZ.

An example of setting the angle formed by the first reflecting surface 41L and the second reflecting surface 41R is that the angle D1 is smaller than a flat angle (180 degrees). In this case, when the scanning light L2R is reflected by the second reflecting surface 41R, it is emitted in the same direction as the axis AZ on the projection surface of FIG. 5 viewed from the direction along the axis AR1. Similarly, when the scanning light L2L is reflected by the first reflecting surface 41L, the scanning light L2L is emitted in the same direction as the axis AZ on the projection surface of FIG. 5 viewed from the direction along the axis AR1.

The outgoing light L3 reflected by the reflecting mirror section 40 is emitted toward the scanning target region R. Under such conditions, the light beam L3 is emitted toward the scanning target region R so that the density of the locus of the outgoing light L3 is high in the central region of the scanning target surface S1. That is, of the scanning trajectory TR drawn by the transmitted light L2 ′ on the virtual surface SS1, the scanning light L2 depicting a dense region having a high trajectory density is directed toward the central region of the scanning target region R, and the sparseness having a low trajectory density is obtained. The angles of the second reflecting

surfaces

41R and 41L are set so that the scanning light L2 that draws the region (the central portion in the scanning locus TR) is directed toward the end of the scanning target region R.

In this embodiment, the optical path of the emitted light L3 reflected by the first reflecting surface 41L is set so as to go directly to the scanning target region R. However, the optical path of the emitted light L3 reflected by the first reflecting surface 41L may not be an optical path directly toward the scanning target region R. For example, an optical member such as a mirror is provided between the reflecting mirror section 40 and the scanning target region R, and the light path is indirectly set so that the emitted light L3 reflected by the first reflecting surface 41L is directed to the scanning target region R. It may be set.

Similarly, the optical path of the outgoing light L3 reflected by the second reflecting surface 41R may not be an optical path directly toward the scanning target region R. For example, an optical member such as a mirror may be provided between the reflecting mirror section 40 and the scanning target region R, and the optical path may be set indirectly so that the emitted light L3 is directed to the scanning target region R.

FIG. 6 shows an emission mode of the scanning light L2 reflected by the reflecting mirror section 40 as viewed from the direction along the axis AR1. The thickness of the arrow in the figure depends on the density of the trajectory. That is, a thick arrow indicates that the locus density is high, and a thin arrow indicates that the locus density is low.

In FIG. 6, the distance between the MEMS mirror device 30 and the reflecting mirror unit 40 is very short compared to the distance between the scanning target surface S1 and the reflecting mirror unit 40. Therefore, it can be said that the scanning light L2 is emitted from the reflecting mirror portion 40, that is, the light emission point, when viewed macroscopically.

The scanning light L2 reflected by the reflecting mirror section 40 is irradiated toward the scanning target surface S1. Specifically, the scanning light L2 is irradiated so that the locus density is highest in the central region of the scanning target surface S1. Further, the scanning light L2 is irradiated so that the density gradually decreases toward the end region along the axis AX1 of the scanning target surface S1.

FIG. 7 shows the locus of the scanning light L2 irradiated on the scanning plane S1 in FIG. In FIG. 7, the scanning target surface S 1 is reflected by the scanning locus region S 1 L drawn by the scanning light L 2 reflected by the second reflecting surface 41 R of the reflecting surface 41 and the first reflecting surface 41 L of the reflecting surface 41. A scanning locus region S1R drawn by the scanned light L2 is shown.

The locus of the scanning light L2 reflected by the second reflecting surface 41R of the reflecting surface 41 is drawn in the scanning region S1L with the positional relationship reversed. Similarly, the locus of the scanning light L2 reflected by the first reflecting surface 41L is drawn in the scanning region S1R with the positional relationship reversed. That is, in the locus of the scanning light L2 irradiated to the scanning surface S1, the positional relationship between the sparse region and the dense region of the locus changes from the positional relationship in the reflecting mirror unit 40. In other words, the reflecting mirror unit 40 can change the positional relationship between the first scanning region Ra and the second scanning region Rb.

Specifically, in FIG. 4A, a sparse region having a low trajectory density of the scanning light L2 is disposed in the central region, and a dense region having a high trajectory density of the scanning light L2 is disposed in the end region. Yes. This corresponds to the locus of the scanning light L2 on the virtual surface SS1. On the other hand, scanning light L2 that describes a dense region having a high trajectory density in the virtual surface SS1 is disposed in the central region of the scanning surface target S1, and the end region of the scanning target surface S1 is in the virtual surface SS1. Scanning light L2 depicting a sparse region with a low locus density is disposed.

By the way, when the angle Y and the angle θ shown in FIG. 5 satisfy the condition of Y = θ / 2, as shown in FIG. 7, in the central region of the scanning plane S1, the region S1L of the scanning locus and the scanning locus The region S1R is arranged so as to be in contact with each other. In such a condition, since the dense region is arranged in the central region of the scanning target region R, it becomes possible to improve the distance measurement accuracy of the object OB in the central region.

The conditions of the angle Y and the angle θ are not limited to Y = θ / 2, and may be appropriately adjusted according to the position that the user wants to watch. For example, when it is intended to further improve the distance measurement accuracy of the object OB in the central region of the scanning target region R, or to look more closely at the target object OB, in the central region of the scanning target region R, the region S1L of the scanning locus The scanning trajectory region S1R may be scanned so as to overlap each other. Specifically, the conditions may be set so as to satisfy Y> θ / 2.

FIG. 8 shows a scanning locus region S1L and a scanning locus region S1R of the scanning target surface S1 in FIG. That is, of the scanning trajectory regions S1L and S1R, the regions with dense scanning trajectories partially overlap. FIG. 8 shows a scanning locus region in which a range in which the scanning locus region S1L and the scanning locus region S1R overlap each other (hereinafter referred to as an overlapping range) is set small. In the overlap range, the distance measuring device 10 can obtain data of both the scanning locus area S1L and the scanning locus area S1R.

For example, the distance measuring device 10 measures data in the other area even if some data may not be obtained in any one of the areas S1L and S1R of the scanning trajectory in the overlap range. It can be used for distance. For this reason, it is possible to reliably obtain distance measurement data in the overlap range.

FIG. 9 shows a scanning locus region S1L and a scanning locus region S1R of the scanning plane S1 in FIG. In FIG. 9, a scanning locus region in which the overlap range is set large is shown. In the overlap range, the distance measuring device 10 can obtain data of both the scanning locus area S1L and the scanning locus area S1R.

Further, as the overlap range becomes larger, the number of scanning lights L2 irradiated on the range also increases. Therefore, it is possible to improve the detection rate of the object OB in the overlap range.

Note that more data can be obtained by shortening the emission interval of the scanning light L2 irradiated in the overlap range. Thus, by shortening the emission interval of the scanning light L2, it is possible to obtain detailed information of the object OB in the overlap range.

By the way, for example, when the scanning light L2 is irradiated onto the hinge H of the reflecting mirror part 40, it is difficult to irradiate only the specific position of the scanning target region R with the scanning light L2. Therefore, the light source control unit 13 may perform control so that the scanning light L2 is not irradiated onto the hinge H.

In the present embodiment, the angle formed between the second reflecting surface 41R irradiated with the two scanning lights L2 emitted at the maximum swing angle around the axis AX and the first reflecting surface 41L changes. Thus, the reflecting mirror part 40 was configured. However, the reflecting mirror portion is changed so that the angle formed between the second reflecting surface 41R irradiated with the two scanning lights L2 emitted at the maximum swing angle around the axis AY and the first reflecting surface 41L changes. 40 may be configured.

When the reflecting mirror unit 40 is configured in this way, it is possible to scan by changing the positional relationship between the dense and sparse regions of the locus formed in the axis AY1 direction (or the axis AX1 direction).

Two examples are given as examples in which the angle formed between the second reflecting surface 41R of the reflecting mirror section 40 and the first reflecting surface 41L changes as described above. Here, the hinges H of the reflecting mirror part 40 may be provided at a plurality of locations. For example, the reflecting mirror unit 40 may be configured by combining two reflecting surfaces 41 having different directions in which the angles formed by the second reflecting surface 41R and the first reflecting surface 41L described above are different from each other.

In these embodiments, two scanning lights emitted at the maximum swing angle of the swing plate SY of the MEMS mirror device 30 or the maximum swing angle of the swing plate SX are L2R and L2L. There is no denying that light is not emitted in the vicinity of the maximum oscillation angle and is emitted within a maximum emission angle smaller than the maximum oscillation angle. In this case, the two scanning lights emitted at the maximum emission angle may be read as L2R and L2L.

When the reflecting mirror unit 40 is configured in this way, scanning can be performed while changing the positional relationship between the dense and sparse regions of the locus formed in the directions of the axes AX1 and AY1.

As described above, according to the scanning device of the present embodiment, the setting condition of the first member 40a and the second member 40b of the reflector part 40 (that is, the first member 40a and the first member 40b of the reflector part 40) is set. The angle formed by the second member 40b) can be freely changed.

More specifically, when the condition of Y = θ / 2 is satisfied, the scanning light L2 is reflected by the reflecting mirror unit 40, thereby making it possible to scan by changing the positional relationship between the dense region and the sparse region. In other words, the scanning light L2 is reflected by the reflecting mirror unit 40, so that the positional relationship between the dense region and the sparse region can be changed and scanned.

The overlap range of the region S1L and the region S1R can be determined by changing the conditions of the angle Y and the angle θ. Specifically, when 0 <Y <θ / 4, the sparse region of the region S1L and the sparse region of the region S1R partially overlap, and when Y = θ / 4, the coarse region of the region S1L The dense region of the region and the region S1R, the dense region of the region S1L, and the sparse region of the region S1R are bulky and overlap with each other, and in the multiple of θ / 4 <Y <θ / 2, A part of the dense region overlaps.

In addition, according to the distance measuring apparatus of the present embodiment, it is possible to perform distance measurement by a scanning mode having a desired density distribution locus in the scanning target region R which is a region for distance measurement. For this reason, it is possible to obtain a good distance measurement state, and it is possible to perform the distance measurement of the object OB in the scanning target region R with higher accuracy.

In the first embodiment, an example has been described in which the angle D1 changes within 180 degrees with respect to the angle facing the emission direction of the emitted light L3 among the angles formed by the second reflection surface 41R and the first reflection surface 41L. However, the angle D1 may be further changed to 180 degrees or more.

FIG. 10 shows an aspect of the scanning light L2 reflected by the reflecting mirror section 40 as viewed from the direction along the axis AR1 of the reflecting mirror section 40. The thickness of the arrow in the figure depends on the density of the trajectory. That is, a thick arrow indicates that the locus density is high, and a thin arrow indicates that the locus density is low. Further, the scanning light L2 traveling toward the first reflecting surface 41L is referred to as first scanning light L2F, and the scanning light L2 traveling toward the second reflecting surface 41R is referred to as second scanning light L2S.

The reflecting surface 41 of the reflecting mirror section 40 is configured so that the emitted light L3 reflected by the second reflecting surface 41R and the emitted light L3 reflected by the first reflecting surface 41L are emitted in directions away from each other. Is formed.

In the present embodiment, the two first reflection surfaces 41L and the second reflection surface 41R of the reflection surface 41 have an angle D1 that faces the MEMS mirror device 30 out of angles relative to each other larger than a flat angle (180 degrees). It has become. An angle obtained by subtracting the angle D1 from 180 degrees is defined as an angle Y. In the present embodiment, the angle Y is a negative value Y <0.

The outgoing light L3 reflected by the reflecting mirror section 40 is emitted toward the scanning target region R. The scanning target region R includes a first scanning region Ra and a second scanning region Rb that are spaced apart from each other. For example, the first scanning region Ra and the second scanning region Rb are separated from each other in the direction along the swing axis AX or the axis AY of the reflecting member of the MEMS mirror device 30.

Since the angle D1 is larger than the flat angle, the optical path of the emitted light L3 reflected by the first reflecting surface 41L is directed to the first scanning region Ra in the scanning target region R. Further, the optical path of the emitted light L3 reflected by the second reflecting surface 41R is directed to the second scanning region Rb.

It should be noted that the size of the angle D1 defines the interval between the first scanning region Ra and the second scanning region Rb, and the larger the angle D1, the wider the interval between the regions Ra and Rb. The magnitude of the irradiation angle θ with respect to the reflecting mirror section 40 of the MEMS mirror device 30 (that is, the magnitude of the swing angle of the reflecting surface 30S of the MEMS mirror device 30) is the first scanning region Ra and the second scanning region. This is reflected in the size of Rb.

FIG. 11 shows an emission mode of the scanning light L2 reflected by the reflecting mirror section 40 as viewed from the direction along the axis AR1. The thickness of the arrow in the figure depends on the density of the trajectory. That is, a thick arrow indicates that the locus density is high, and a thin arrow indicates that the locus density is low.

In FIG. 11, the distance between the MEMS mirror device 30 and the reflecting mirror unit 40 is very short compared to the distance between the scanning target surface S and the reflecting mirror unit 40. Therefore, it can be said that the scanning light L2 is emitted from the reflecting mirror portion 40, that is, the light emission point, when viewed macroscopically.

The scanning light L2 reflected by the reflecting mirror unit 40 is emitted toward the scanning target surface S as outgoing light L3. The scanning target surface S includes a first scanning surface Sa disposed on the first scanning region Ra side and a second scanning surface Sb disposed on the second scanning region Rb side.

The outgoing light L3 obtained by reflecting the scanning light L2 on the first reflecting surface 41L is irradiated toward the first scanning region Ra. Similarly, the emitted light L3 reflected by the scanning light L2 by the second reflecting surface 41R is irradiated toward the second scanning region Rb.

FIG. 12 shows the locus of the emitted light L3 irradiated on the scanning target surface S in FIG. In FIG. 12, the scanning target surface S is reflected by the region S1L where the scanning locus is drawn by the emitted light L3 reflected by the second reflecting surface 41R of the reflecting surface 41 and the first reflecting surface 41L of the reflecting surface 41. A region S1R in which a scanning locus is drawn by the emitted light L3 is shown.

That is, the reflecting surface 41 is bent so that the angle D1 between the first reflecting surface 41L and the second reflecting surface 41R facing the MEMS mirror device 30 is 180 degrees or more, that is, Y <0. As a result, the first scanning region Ra and the second scanning region Rb in different directions are scanned.

By setting such a condition, the MEMS mirror device 30 scans when the scanning target region R is scanned by emitting the scanning light L2 at the maximum swing angle around the axis AX or AY of the light reflecting surface 30S. It is possible to scan the first scanning region Ra and the second scanning region Rb, which are regions that cannot be separated from each other.

In addition, about the area | region between 1st scanning area | region Ra and 2nd scanning area | region Rb of the scanning object area | region R, you may measure the target object OB by scanning with another ranging device, for example. In this way, for example, the region between the first scanning region Ra and the second scanning region Rb in the scanning target region R is scanned, and the first scanning region Ra and the second scanning region Rb are scanned. Scanning can be performed simultaneously.

As described above, the distance measuring device 10 of the present invention scans the scanning target region R by reflecting the scanning light L2 emitted from the MEMS mirror device 30 with the reflecting mirror unit 40.

The optical path of the outgoing light L3 reflected by the second reflecting surface 41R is set so as to be directed to the first scanning region Ra in the scanning target region R. Further, the optical path of the emitted light L3 reflected by the first reflecting surface 41L is set so as to go to the second scanning region Rb.

Therefore, the MEMS mirror device 30 scans the scanning target region R by emitting the scanning light L2 at the maximum swing angle around the first swing axis AX or the second swing axis AY of the light reflecting surface 30S. In this case, it is possible to scan the first scanning region Ra and the second scanning region Rb that are separated from each other, which are regions that cannot be scanned. As a result, the first scanning region Ra and the second scanning region Rb that are separated from each other can be scanned by one MEMS mirror device 30.

In the present embodiment, the first scanning region Ra and the second scanning region Rb are set under the condition that the angle D1 between the first reflecting surface 41L and the second reflecting surface 41R is 180 degrees or more, that is, Y <0. Said about the separation. Even if Y> θ / 2 in the configuration of the first embodiment, the first scanning region Ra and the second scanning region Rb can be separated from each other, and this is not denied. In this case, when viewed macroscopically, the first scanning region Ra and the second scanning region Rb are reversed.

In Example 1, the first member 40a and the second member 40b of the reflecting mirror part 40 are connected via a hinge H. However, the configuration of the reflecting mirror section 40 is not limited to the configuration as long as the second reflecting surface 41R and the first reflecting surface 41L have relatively variable angles with respect to each other.

FIG. 13 shows a configuration example of the reflecting mirror unit 40 according to the present embodiment. The reflecting mirror part 40 shown in FIG. 13 is different from the reflecting mirror part 40 shown in FIG. Since other configurations are the same, the same reference numerals are given and description thereof is omitted.

The first member 40a has a rod-shaped first shaft SH1 formed along the axial direction of the first rotation axis AR1. One end of the first shaft SH1 is connected to an actuator (not shown), and is rotatable around the first rotation axis AR1. That is, the first member 40a is configured to be rotatable around the axis of the first shaft SH1. In other words, the second reflecting surface 41R is provided so as to be rotatable about the first rotation axis AR1.

The second member 40b has a second shaft SH2 formed along the axial direction of the second rotation axis AR2 parallel to the first rotation axis. One end of the second shaft SH2 is connected to an actuator (not shown) and is rotatable around the second rotation axis AR2. The second member 40b is configured to be rotatable around the axis of the second shaft SH2. In other words, the first reflecting surface 41L is provided to be rotatable about the second rotation axis AR2.

The first rotation axis AR1 and the second rotation axis AR2 are set conditions for the second reflection surface 41R and the first reflection surface 41L described in the first and second embodiments, Y = θ / 2, Y> θ / 2 or Y <θ / 2 may be set as long as the aspect can be satisfied. That is, the first rotation axis AR1 may be on the proximal side as viewed from the second member 40b of the first member 40a, or on the distal side as viewed from the second member 40b of the first member 40a. May be. Similarly, the second rotation axis AR2 may be proximal to the first member 40a of the second member 40b or distal to the first member 40a of the second member 40b. May be on the side.

A gap may be provided between the first member 40a and the second member 40b so as not to prevent the rotation of each member. The light source control unit 13 may control so that the gap between the first member 40a and the second member 40b is not irradiated with the scanning light L2. When there is no gap between the first member 40a and the second member 40b, the first rotation axis AR1 is provided on the proximal side when viewed from the second member 40b of the first member 40a. The second rotation axis AR2 may be provided on the proximal side when viewed from the first member 40 of the second member 40b. By doing in this way, it can prevent that the 1st member 40a and the 2nd member 40b mutually interfere.

Further, in order to prevent the scanning light L2 from being irradiated to both the first reflection surface 41L and the second reflection surface 41R, the gap between the first member 40a and the second member 40b is: It is preferable to provide at least the spot diameter of the scanning light L2.

In the present embodiment, the first member 40a and the second member 40b are rotated using an actuator. However, the mechanism for rotating the first member 40a and the second member 40b is not limited to the actuator, and may be, for example, an electromagnetic mechanism.

As described above, according to the scanning device of the present embodiment, the setting conditions for the first member 40a and the second member 40b of the reflecting mirror section 40 can be freely changed. In other words, it is possible to perform scanning and ranging according to the situation.

Specifically, as in the first embodiment, when the condition of Y = θ / 2 is satisfied, the scanning light L2 is reflected by the reflecting mirror unit 40, thereby changing the positional relationship between the dense region and the sparse region. It becomes possible to do.

When the condition of 0 <Y <θ / 2 is satisfied, scanning can be performed so that the scanning locus region S1L and the scanning locus region S1R overlap each other.

Further, similarly to the second embodiment, when the condition of Y <0 is satisfied, the first scanning region Ra and the second scanning region Rb that are separated from each other can be scanned by one MEMS mirror device 30. .

Modified example

According to the first to third embodiments, the angle of the second reflecting surface 41R and the first reflecting surface 41L of the reflecting mirror section 40 relative to each other is variable, and the angle is obtained by being driven by an actuator (not shown). Can be changed dynamically. Accordingly, by changing the angles of the second reflecting surface 41R and the first reflecting surface 41L, the density distribution of the scanning trajectory in the scanning target region R is changed (when the angle D1 is smaller than the flat angle), or scanning. Can be changed (when the angle D1 is larger than the flat angle).

Therefore, the distance measuring device 10 changes the overlap of the scanning trajectory by adjusting the angles of the second reflecting surface 41R and the first reflecting surface 41L according to the surrounding environment and the purpose of use, for example. Also good. Specifically, when the distance measuring device 10 is mounted on a moving body, it is necessary to perform a detailed distance measuring operation on the central portion (front portion) as viewed from the distance measuring device 10 in the scanning target region R. In a case (for example, when the moving body travels on a highway or moves at a high speed), the scanning locus region S1L and the scanning locus region S1R are scanned so as to overlap each other.

On the other hand, when there is an object for distance measurement as viewed from the distance measuring device 10 in the scanning target region R (for example, when the moving body is traveling on a road with many pedestrians, or when moving slowly ), By making the angle D1 of the second reflecting surface 41R and the first reflecting surface 41L larger than the flat angle, it becomes possible to appropriately detect the distance from the object existing on the side of the moving body. Further, by changing the angle D1 for each scanning period by the MEMS mirror device 30, scanning may be performed as a wider range-finding region R. By periodically changing the angle D1, distance measurement can be performed with a wider range than the range that can be scanned by one conventional MEMS mirror device.

DESCRIPTION OF SYMBOLS 10 Distance measuring device 30 MEMS mirror device 40 Reflective mirror part 40a 1st member 40b 2nd member 41L 1st reflective surface 41R 2nd reflective surface 50 Light-receiving part 60 Distance measuring part AR1 1st rotation axis AR2 1st 2 pivots

Claims

An emission part for emitting light;
An optical scanning unit that irradiates the light toward the first region and the second region adjacent to each other by periodically changing the irradiation direction of the light;
The first scanning light emitted toward the first region from the optical scanning unit is guided to the first scanning region, and the second scanning light emitted toward the second region is supplied to the second scanning region. An optical path controller that leads to
Have
The optical path control unit is configured to change a positional relationship between the first scanning region and the second scanning region by changing an optical path of the first scanning light and the second scanning light. A scanning device characterized by comprising:
The optical path control unit includes a first reflection surface and a second reflection surface that reflect light emitted from the optical scanning unit,
The first reflecting surface and the second reflecting surface are configured to be able to change an angle formed with respect to an incident direction of the light to the optical path control unit. The scanning device according to claim 1.
3. The scanning apparatus according to claim 2, further comprising a driving unit that changes an angle formed by the first reflecting surface and the second reflecting surface.
The first reflection surface and the second reflection surface are connected by a hinge so that an angle with respect to an incident direction of the light to the optical path control unit can be changed. The scanning device according to claim 2 or 3, wherein the scanning device is characterized in that:
4. The structure according to claim 3, wherein an angle with respect to an incident direction of the light can be changed by rotating each of the first reflecting surface and the second reflecting surface. 5. Scanning device.
6. The scanning device according to claim 2, wherein an angle formed by the first reflecting surface and the second reflecting surface is periodically changed.
An emission part for emitting light;
An optical scanning unit that irradiates the light toward the first region and the second region adjacent to each other by periodically changing the irradiation direction of the light;
The first scanning light emitted toward the first region from the optical scanning unit is guided to the first scanning region, and the second scanning light emitted toward the second region is supplied to the second scanning region. An optical path controller that leads to
A light receiving unit that receives reflected light reflected by an object existing in the first scanning region or the second scanning region, the first scanning light or the second scanning light;
A distance measuring unit that measures a distance to the object based on reflected light received by the light receiving unit;
Have
The optical path control unit is configured to change a positional relationship between the first scanning region and the second scanning region by changing an optical path of the first scanning light and the second scanning light. A distance measuring device characterized by that.